Full screen in Resolve 15.0.1 hangs

I recently acquired a three monitor setup - (2) BenQ BL2711U and (1) BenQ PV3200PT. I have a BMD DeckLink Mini Monitor 4K card that is driving the PV3200 via HDMI which will allow me to display full screen output.

I'm at a point where I cannot get Resolve to give me support for all three monitors. When I attempt to click on Dual Screen, and then On, Resolve hangs. Resolve will display the main UI on my main display and the full screen content on the monitor attached to the DeckLink, but not on my 3rd monitor. I've tried disabling the DeckLink in Preferences, but it made no difference. While it displays on two monitors, the UI is completely hung and has to be killed via task manager.

I've tried changing the primary display to a different monitor to no avail. The odd thing is that I had this briefly working yesterday, but only briefly. Now it's consistent and will hang everytime. I've tried uninstalling Resolve, deleting all preferences, disabling the DeckLink card in device manager - nothing helps.

My GPU setup is two NVIDIA GeForce GTX 1080 Ti(s) in an SLI configuration. I'm running Windows 10 RS4 (17134.) I just updated my NVIDIA drivers today in hope that it might fix it, but nothing. Same thing with Resolve - updated to 15.0.1 today.

Because I have software development experience, I attached a debugger to resolve.exe and found that one thread was stuck executing the following stack (reduced for readability.) Resolve consumes about 3% CPU while it's hung.

Please let me know if I can provide any logs or other information.

--Raymond

0:270> ~0k
# Child-SP RetAddr Call Site
00 00000044`986fa6c8 00007ffd`f337697c win32u!NtUserEnumDisplayMonitors+0x14
*** ERROR: Symbol file could not be found. Defaulted to export symbols for C:\ProgramData\A-Volute\Modules\ScheduledModules\x64\NahimicOSD.dll -
01 00000044`986fa6d0 00007ffd`eb242f1b d3d9!CEnum::GetAdapterMonitor+0x7c
02 00000044`986fa720 00007ffd`eb2417a2 NahimicOSD!GetHotPatchInfo+0xde4b
03 00000044`986fa780 00007ffd`eb23de3d NahimicOSD!GetHotPatchInfo+0xc6d2
04 00000044`986fa7c0 00007ffd`fae17c0e NahimicOSD!GetHotPatchInfo+0x8d6d
*** WARNING: Unable to verify checksum for D:\Program Files\Blackmagic Design\DaVinci Resolve\Qt5Gui.dll
*** ERROR: Symbol file could not be found. Defaulted to export symbols for D:\Program Files\Blackmagic Design\DaVinci Resolve\Qt5Gui.dll -
05 00000044`986fa830 00007ffd`cf144cda gdi32full!SwapBuffers+0x2e
06 00000044`986fa860 00007ffd`cf319f54 Qt5Gui!QOpenGLContext::swapBuffers+0x17a
*** WARNING: Unable to verify checksum for D:\Program Files\Blackmagic Design\DaVinci Resolve\Qt5Widgets.dll
*** ERROR: Symbol file could not be found. Defaulted to export symbols for D:\Program Files\Blackmagic Design\DaVinci Resolve\Qt5Widgets.dll -
07 00000044`986fa8b0 00000000`71f3e3cb Qt5Gui!QPlatformBackingStore::composeAndFlush+0x784
08 00000044`986faa40 00000000`71f3c80e Qt5Widgets!QWidgetPrivate::moveRect+0x7fb
09 00000044`986faaf0 00000000`71f3c59d Qt5Widgets!QApplication::windowIcon+0x199e
0a 00000044`986fab50 00000000`71f3f22b Qt5Widgets!QApplication::windowIcon+0x172d
0b 00000044`986faf20 00000000`71f711e7 Qt5Widgets!QWidget::size+0x48b
0c 00000044`986faf70 00000000`71f804a5 Qt5Widgets!QWidgetPrivate::syncBackingStore+0x47
0d 00000044`986fafa0 00000000`71f36026 Qt5Widgets!QSizePolicy::QSizePolicy+0x8d5
0e 00000044`986fb000 00000000`71f35558 Qt5Widgets!QApplicationPrivate::notify_helper+0xf6
*** ERROR: Symbol file could not be found. Defaulted to export symbols for D:\Program Files\Blackmagic Design\DaVinci Resolve\Resolve.exe -
0f 00000044`986fb030 00007ff7`053b6570 Qt5Widgets!QApplication::notify+0x1e98
*** WARNING: Unable to verify checksum for D:\Program Files\Blackmagic Design\DaVinci Resolve\Qt5Core.dll
*** ERROR: Symbol file could not be found. Defaulted to export symbols for D:\Program Files\Blackmagic Design\DaVinci Resolve\Qt5Core.dll -
10 00000044`986fb6c0 00000000`72670fe8 Resolve!xmlMemoryStrdup+0x10f7b90
11 00000044`986fbcd0 00007ffd`cf114c7e Qt5Core!QCoreApplication::notifyInternal+0x78
12 00000044`986fbd50 00007ffd`cf1179b7 Qt5Gui!QGuiApplicationPrivate::processExposeEvent+0x10e
13 00000044`986fbdf0 00007ffd`cf103b3e Qt5Gui!QGuiApplicationPrivate::processWindowSystemEvent+0xf7

[Peter Chamberlain]

Can u disable the SLI

Also, u can generate a diagnostic log we will look at from the help menu after a crash.

Disabling the SLI appears to have corrected the problem. I confirmed that the problem existed with only two displays (so nothing connected to the DeckLink) and then I disabled the SLI and Resolve spans both displays.

I'll attach the third display again and see if the full screen output works.

Thanks for the prompt reply. I mentioned about the debugger - it was not a crash - Resolve was hung, so I attached to the debugger to see what it was doing.

The fix was only temporary, unfortunately.

After I rebooted to restore applications that I had to terminate to disable the SLI, Resolve would not run split screen and hung again.

Afterward, I decided to try to re-enable the SLI, avoiding the reboot, and then ran Resolve just to see what happened and it worked. Too bad I can't run without rebooting forever. If nothing else, I should be able to limp along by disabling the SLI and not rebooting.

Any help is greatly appreciated.

[Peter Chamberlain]

Its normal to not have SLI on with Resolve and of course you can reboot so my guess is there is something in the Nvidia driver that need changing, or a new driver.